Return parcel to amazon tracking

This is a question from a customer, not a seller

I returned a couple of phone battery chargers 2 weeks ago. when I selected the return Amazon said once returned I would be eligible for up to £4.49 shipping refund

I, therefore, packaged it up, printed the label, and processed it through click and drop with the rest of my mail

I have the 2d tracking which so far shows undelivered.

There is nowhere in Amazon to add the tracking for the return
The return status shows that it has to be returned by today.

Has anyone ever had this as being a buyer return?

I can take a screenshot of the click and drop batch showing the tracking. I can also print the label, but how can I prove to Amazon that I have returned the goods if Royal Mail haven’t scanned the parcel, when there is nowhere to even add the tracking

one rule for sellers, one ruile for Amazon it seems
They can just say they never received it (even though I have the label)